Abstract
The biochemical, serological and genetic characteristics of six strains of Pseudomonas anguilliseptica isolated from cod, Gadus morhua , in Scotland were compared to well characterized isolates of this same bacterial species but of different origin. Biochemical and physiological analyses showed that this group of isolates was highly homogeneous, their characteristics matching previous descriptions of the pathogen. Similar results were obtained for the six cod isolates in the serological assays, all of them belonging to the serotype O1. Marked homogeneity was observed also in the genetic study, analysed by means of RAPD, ERIC‐PCR and REP‐PCR procedures, showing that they were similar to isolates from gilthead seabream, Sparus aurata , black spot seabream, Pagellus bogaraveo , and turbot, Psetta maxima . Virulence assays demonstrated that the cod isolates were highly pathogenic for turbot and sole, Solea senegalensis, with LD 50 between 7.6 × 10 4 and 5 × 10 7 bacterial cells per fish.